<?php
if ($file->type === 'php') {
    echo '<div class="content">';
    highlight_string ( $file->content );
    echo '</div>';
} else if (in_array ( $file->type, array ('txt', 'js', 'css' ) )) {
    echo '<div class="content">';
    echo nl2br ( $file->content );
    echo '</div>';
} else
    echo '<div class="error">Preview is not available for this file type.</div>';
?>